Variable-speed-transmission device.



W. W. PRATHER. VARIABLE SPEED TRANSMISSION DEVICE. APPLIOATION FILEDPEB.23, 1910.

1,012,912. Patented Dec.26, 1911.

ii/Z M WILBUR W. PBATHER, 0F ADAMS SPRINGS, CALIFORNIA. 1

VARIABLE-SPEED-TRANSMISSION DEVICE.

Specification of Letters Patent.

Patented Dec. 26, 1911.

Application filed February 23, 1910. Serial No. 545,285.

To all whom '52! mag) concern:

Be it known that I, WILBUR W. PRATHER, a citizen of the United States,residing at Adams Springs, in the county of Lake and State ofCalifornia, have invented new and useful Improvements in Variable-Speed- Transmission Devices, of which the following is a specification.

This invention relates to transmission devices and the object of theinvention is to produce a device of this class which can be readilyadjusted so as to vary the speed of driving.

The invention is particularly applicable to motorcycles em loying a beltdrive and is particularly use 1 in this connection for the reason thatthe device performs the function of a clutch for it operates to preventthe transmission of power in certain positions. This gives it greatutility when used in motorcycles. for the reason that I produce theeffect of a combined clutch and transmission.

In the annexed drawing which fully illustrates my invention, Figure 1 isa side ele' vation showing parts of the motorcycle to which my inventionhas been applied. Fig. 2 is a longitudinal section taken through thehorizontal axis of my transmission device, and showing details of itsconstruction, certain parts being omitted. Fig. 3 is a side elevation ofa pair of adjusting collars by means of which the device is adjusted soas to transmit the power at difi'erent speeds.

Referring more particularly to the parts, 4 represents the frame of themotorcycle, which may be of usual construction. As indicated at theusual point a crank case 5 is provided above which an engine or motor 6is mounted. From. the crank case 5, a tapered stub shaft 7 projects, andon this stub shaft 7 I attach a hub 8. At its end adjacent to the crankcase 5, the hub 8 is formed into a cone or collar 9, and at its otherend it is provided with a tubular neck or extension 10. The hub 8 issecurely held by a hub nut 11 mounted on the end of the shaft 7, asshown. The outer extremity of the neck 10 is threaded so as to receive athrust nut 12, which is rigidly secured to the neck as indicated.Opposite the cone or collar 9 I provide a similar collar 13, the hub 14of which is offset so as to form an annular chamber 15 around the hub 8,and the hub 14 is further provided with a tubular extension or sleeve16, which is mounted to slide on the neck 10, as shown. The neck 10 isprovided with a feather or spline 17, which is received in acorresponding groove in the sleeve 16, so that the collar or cone 13 isnonrotatable on the neck, although it can slide freely thereupon, aswill be readily understood. I

The hub 14 presents an. annular face or shoulder 18 adjacent to which aball ring 19 is mounted loosely around the sleeve 16, and this 'ballring is provided with a plurality of openings receiving loose balls 20,as shown. A similar ball ring 21 is provided adjacent to the fixedcollar 12 and this ring is provided with loose balls 22, which run onthe inner face of the collar 12, as shown. Between the rings 19 and 21,a pair of adjusting collars 23 and 24 are mounted, the latter collarbeing disposed near the outer end of the neck 10. The collar 23 isloosely mounted on the sleeve 16, while tlie collar 24 is looselymounted on the'neck 10,

as indicated. The collar 23 is provided with a radially projecting arm25, and this arm is connected by a link 26 with the outer side of thecase 5 by means of a suitable pivot bolt 27. A loose pivot connection 28is formed for connecting the link 26 to the arm, which will permit thecollar 23 to slide inwardly or outwardly on the sleeve 16. This slidingmovement may be given to the collar 23 by rotating the collar 24 in thedirection of the arrow indicated in Fig. 3.

' In order to rotate this collar it is provided with a radial arm 29,which is connected by a link 30 with the hand lever 31, said hand leverbeing pivotally mounted at 32 near the forward edge of the crank case.This hand lever 31 extends upwardly and is provided with a lockingdevice 33 cotiperating with the fixed segment 34, which enables thelever to be locked in any position desired. The sliding movement of thecollar 23 is imparted to it by means of inclined teeth 35, which aireformed on the collar 24 and mesh with corresponding inclined teeth 36formed on the collar 23. These teeth have inclined faces and abruptfaces, as shown.

On the hub 8 adjacent to the cone 9, a circumferential groove or ballrace 37 is formed in which run a plurality of balls 38, and on the outerside of these balls a hub ring 39 is loosely mounted, said. hub. ringhaving a groove 39* for the balls shown. This hub ring is ofsufficiently small diameter to be received in the chamber 15 when thecone 13 advancesunder the action of the-collar The members 9 and 13 arein the form offlat cones, and they constitute a driving pulley adaptedto receive a driving belt 40015 the form indicated. The form of thisbelt in cross section is indicated in Fig. 2. It presents fiat sidewalls 41, which diverge from each other, and these side walls areadapted to lie against the cones 9 and 13 as indicated. These side walls41 are integrally connected with an inner wall 42, which may run on theball ring 39 and are connected near their outer edges with an outer wall43 so that the belt presents the tapered form indicated.

On the pivot 32 of the lever 31, a belttightener is attached, the samebeing in the form of a bell-crank lever having an arm 44, which projectsunder the forward end of the belt 40. This arm is provided with a pulley45, which rests against the end run of the belt, as shown. The belttightener also has. an upwardlyextending arm 46, and this arm isconnected by a spring 47 with the lever 31, as indicated. As representedin Fig.

2 the collars 9 and 13 are separated so that the belt 41 is running onthe ring 39 with out transmitting power from the pulley to the rearwheel 48 of the motorcycle. WVhen in this relation the lever 31 would bein a position opposite to that in which it is shown in Fig. 1 with thepulley 45 pressed upwardly against the lower run of the belt, so

as to take up the slack thereof. In Fig. 3 the adjusting collars 23 and24 are shown in the position which they will have when the belt 40 isrunning on the loose ring 39. Under these circumstances no power will betransmitted and the pulley composed of the cones 9 and 13 willconstitute an open clutch.

When it is desired to start up the motorcycle while the engine isrunning, it will only be necessary to rotate the adjusting collar 24 inthe direction indicated by the arrow in Fig. 3. This will slide thesleeve 16 and the cone 13 toward the left. As the cone 13 moves towardthe left the belt 40 will be forced outwardly automatically as it were,toward the conical faces of the two cones, so that it will beheld insome position removed from the ring 39. It will then transmit power fromthe driving pulley to the rear wheel 48 and the speed of transmission ofthe wheel will depend on the position of the belt, that is, if thebeltmoves out t3 the extreme edge of the pulley formed by the cones, asindicated in Fig. 1, the transmission will take place at the greatestpossible speed. The speed of transmission at an intermediate position ofthe. belt will be pro portional 0 course to, theradius at which the beltis located on the driving pulley. As the cone 13 advances, the ring 39is received in the chamber 15 of the hub 14. The thrust of the collar 23on the .hub 14 is of course taken up at the balls 20 and 22 so that thegreatly reducedigi Special. attention iscalled to the .fact t when thecone 13;;a'dvances toward the cone;

9, the eflect is produced jof closing a clutch 'ill at this point whichbrings the drive gradually into operation at the lowest speed. This is aparticularly advantageous manner. of starting up the device, and as thespeed increases the cone 13 can be advanced farther and farther untilthe motorcycle is finally running at its maximum speed, with the belt atthe outer edge of the driving pulley. I

Attention is called to the cooperative action of the belt tightener,which results in always maintaining a certain amount of tension in thebelt 40. This tension operates to return the cone 13 to its normalposition and keeps the shoulder 18 up against the balls 20 asthe collar23 is returning to its normal position.

It should be understood also that forcing the collar 13 toward thecollar 9 does not produce end thrust against the shaft of the engine forthe reason that the adjusting collars 23 and 24 are arranged to take thethrust which they exert on their side faces; the collar 24'tends to pullthe collar 9 toward the collar 13 with the same force that the adjustingcollar 23 tends to force the collar 13 toward the collar 9.

Having described my invention what I claim as new and desire to secureby Letters Patent is:

1. In combination, a driving shaft, 9. driving pulley mounted thereonhaving a fixed collar, a movable collar and a laterally projectinghollow shaft portion, a pair of adjusting collars mounted upon thehollow shaft and having inclined teeth on their adjacent sides,.means.for anchoring one of said collars to a fixed support adjacent to themechanism, a lever mounted adjacent to the mechanism and connected withthe other collar and adapted to move it back and forth with respecttothe anchored collar, the collars of the said driving pulley havinginclined faces on their adjacent sides, a belt received between saidinclined faces, and driven by said pulley, a belt tightener co operatingwith said belt for controlling its slack, the said tightener cooperatingwith said belt for controlling its slack, the said tightener beingpivotally mounted with respect to the collar actuating lever, and aspring for connecting one end of the tightener with the said leverwhereby the tightener is moved with a resilient action when the lever isadjusted.

2. In combination, a driving shaft, a driving pulley mounted thereuponhavin a fixed co lar and a sliding collar a pair 0 adjusting collarsmounted coaxially with respect to said shaft and having inclined teethon their adjacent sides, means for fixing one of 5 ed to advance saidmovable collar, said p,ul-

ley collars ha inclined faces on their adjacent sides, a elt receivedbetween said conical faces and driven by said pulley, a belt tightenercooperating with said belt to go take up the slack thereon when saidpulley collars are remotely separated, and a resili ent connectionbetween said lever and said belt tightener.

In witness that I claim the foregoing I have hereunto subscribed my namethis 15th 1 day of February, 1910.

WILBUR W. PRATHER. Witnesses:

F. D. AMMEN, EDMUND A. STRAUBE.

